1. Field of the Invention
The invention relates to a device for forming a fabric edge with two doup ends and one stationary thread in which there are thread guides for the doup ends and the stationary thread, the doup ends can be twisted together after every second weft insertion with the crossing of the stationary thread, the thread guides for the doup ends and the thread guides for the stationary thread are fitted to pivot towards each other to form a shed between the doup ends on the one hand and the stationary thread on the other.
2. Description of the Related Art Including Information Disclosed Under 37 CFR .sctn..sctn. 1.97-1.99
Devices for forming a doup edge are known in many different embodiments.
A device for forming a doup edge and provided with two doup ends and one stationary thread is known from DE-GM 85 05 367. In this case, the doup ends are guided by oblique slots for guiding the doup ends superposed crosswise in a connecting link and by a so-called stationary thread needle for receiving the stationary thread. The disadvantage of this device is that the threads have to be deviated.
Another device for forming a fabric edge is known from DE-OS 31 08 662; hereby a pivoting connecting link is provided, that receives the two doup ends. Above the pivoting connecting link a needle guides the stationary thread. The disadvantage thereof is that at least the stationary thread has to be deviated sharply at least twice.
DE 40 38 256 shows a similar construction; at least the stationary thread has to be sharply deviated twice in this construction too, so that the risk of thread breakage exists, depending on the thread used.
A device of the type specified above is known from U.S. Pat. No. 4,869,297. This device has a vertically placed needle with an eye at one end for guiding the stationary thread. Furthermore, two doup ends are provided which are guided through a trunk with two eyes. The space between the two eyes is such that the needle can penetrate between the two doup ends guided by the trunk. The trunk is rotatably designed for tying.
The disadvantage of this device is that the stationary thread is deviated sharply twice when reaching a final position, namely once, when the thread leaves the eye and the second time when the stationary thread is deviated through the trunk in the area of the lower end of the needle. This leads without fail to thread breakage, particularly where yarns of minor quality or glass fiber filaments are used.